\begin{table}%t8
%\centering
\par
\caption {\label{tab_vr_nfields}Field to field variance. } 
%\centerline
 {\begin{tabular}{cc c c c c c} 
\hline\hline
\noalign{\smallskip}
$v_r$ LF(a)/$N_{\rm clusters}$ & 1 & 6 & 10 & 20 & 50 & 100 \\
\hline
$z=6$ \\
Shallow  & $50^{\rm +3}_{-3}$\% & $28^{\rm +1}_{-1}$\% & $24^{\rm +1}_{-1}$\% & $19^{\rm +0}_{-0}$\% & $14^{\rm +0}_{-0}$\% & $10^{\rm +0}_{-0}$\%  \\
Deep & $25^{\rm +1}_{-1}$\% & $17^{\rm +0}_{-0}$\% & $15^{\rm +0}_{-0}$\% & $12^{\rm +0}_{-0}$\% & $9^{\rm +0}_{-0}$\% & $7^{\rm +0}_{-0}$\%  \\
$z=7$ \\
Shallow & $62^{\rm +2}_{-2}$\% & $33^{\rm +1}_{-1}$\% & $28^{\rm +1}_{-1}$\% & $22^{\rm +0}_{-0}$\% & $16^{\rm +0}_{-0}$\% & $12^{\rm +0}_{-0}$\% \\
Deep & $29^{\rm +1}_{-1}$\% & $19^{\rm +0}_{-0}$\% & $17^{\rm +0}_{-0}$\% & $13^{\rm +0}_{-0}$\% & $10^{\rm +0}_{-0}$\% & $7^{\rm +0}_{-0}$\% \\
$z=8$ \\
Shallow & $75^{\rm +3}_{-3}$\% & $39^{\rm +1}_{-2}$\% & $32^{\rm +1}_{-1}$\% & $25^{\rm +0}_{-1}$\% & $18^{\rm +0}_{-0}$\% & $13^{\rm +0}_{-0}$\% \\
Deep & $32^{\rm +1}_{-1}$\% & $21^{\rm +0}_{-0}$\% & $18^{\rm +0}_{-0}$\% & $15^{\rm +0}_{-0}$\% & $11^{\rm +0}_{-0}$\% & $8^{\rm +0}_{-0}$\% \\
%\end{tabular}
%\end{table}